10 awg ampacity and derating

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yankeeman411

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Can someone let me know if im correct please. A 10 awg thhn is good for 40 amps but because of the note it can onlt be put on a 30 amp breaker. But as far as derating i can ise it at 40 amps. I have 20 10 awg thhn in a inch and a quarter which as far as derating is 50 percent. So if i put my 10 wire on a 20 amp breaker im good.

Correct?
 
yankeeman411 said:
Can someone let me know if im correct please. A 10 awg thhn is good for 40 amps but because of the note it can onlt be put on a 30 amp breaker. But as far as derating i can ise it at 40 amps. I have 20 10 awg thhn in a inch and a quarter which as far as derating is 50 percent. So if i put my 10 wire on a 20 amp breaker im good.

Correct?
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as far as ampacity adjustment solely due to number of current carrying conductors in a conduit, I think you are fine.
 
yankeeman411 said:
Can someone let me know if im correct please. A 10 awg thhn is good for 40 amps but because of the note it can onlt be put on a 30 amp breaker. But as far as derating i can ise it at 40 amps. I have 20 10 awg thhn in a inch and a quarter which as far as derating is 50 percent. So if i put my 10 wire on a 20 amp breaker im good.

Correct?
Click to expand...
Your #10 ampacity would fall below 20 amps if you had more than 20 CCC's not 20 conductors so if you only have 20 conductors you're good whether they're considered current carrying or not.
 
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